SPLOT: a Snapshot survey for Polarised Light in Optical Transients

Abstract

We present SPLOT, a small scale pilot survey to test the potential of snapshot (single epoch) linear imaging polarimetry as a supplementary tool to traditional transient follow-up. Transients exist in a vast volume of observational parameter space and polarimetry has the potential to highlight sources of scientific interest and add value to near real-time transient survey streams. We observed a sample of $\sim 50$ randomly selected optical transients with the EFOSC2 and SofI instruments, on the 3.6m New Technology Telescope (NTT) to test the feasibility of the survey. Our sample contained a number of interesting individual sources: a variety of supernovae, X-ray binaries, a tidal disruption event, blazar outbursts, and, by design, numerous transients of unknown nature. We discuss the results, both for the individual sources and the survey in detail. We provide an overview on the success and limitations of SPLOT and also describe a novel calibration method for removing instrumental polarisation effects from Nasymth-mounted telescopes. We find that a SPLOT-like survey would be a benefit to the large scale future transient survey streams such as LSST. The polarimetric measurements have added scientific value to a significant number of the sources and, most importantly, has shown the potential to highlight unclassified transient sources of scientific interest for further study.

Accepted in MNRAS. 20 pages, 10 figures, 3 tables. Also contains a 10 page, two part appendix with unpolarised standard star measurements used for calibration (A) and individual source information and light curves (B). Corrected more typos

References in corpus (16)

• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The Gaia mission
• Gaia Data Release 2: The astrometric solution
• The Pan-STARRS1 Surveys
• Spectropolarimetry of Supernovae
• PESSTO : survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects
• Circular polarization in the optical afterglow of GRB 121024A
• The unpolarized macronova associated with the gravitational wave event GW170817
• Optical and Near-Infrared Polarimetry of Highly Reddened Type Ia Supernova 2014J: Peculiar Properties of Dust in M82
• Linear spectropolarimetry of polarimetric standard stars with VLT/FORS2
• Polarised infrared emission from X-ray binary jets
• The evolution of the 3D shape of the broad-lined type Ic SN 2014ad
• Continuum Foreground Polarization and Na~I Absorption in Type Ia SNe
• ANTARES: Progress towards building a `Broker' of time-domain alerts
• The conventions for the polarization angle
• Calibration of EFOSC2 broadband linear imaging polarimetry

Cited by in corpus (10)

• Polarized kilonovae from black hole-neutron star mergers
• Spectropolarimetry of the tidal disruption event AT 2019qiz: a quasispherical reprocessing layer
• Optical polarization from colliding stellar stream shocks in a tidal disruption event
• Polarimetry of relativistic tidal disruption event Swift J2058+0516
• RINGO3 polarimetry of very young ZTF supernovae
• Modeling continuum polarization levels of tidal disruption events based on the collision-induced outflow mode
• Linear and circular polarimetry of the optically bright relativistic Tidal Disruption Event AT 2022cmc
• Revisiting the unification of tidal disruption events with polarimetry
• Spectropolarimetry of stripped envelope core collapse supernovae and their progenitors
• Science with a large field-of-view polarization survey: The Large Array Survey Telescope Polarization Node (LAST-P)